Add Node menu closes when a Node is selected and the parent foldout is closed in the Graph Toolkit window

Steps to reproduce:

1. Create a new Unity project using the Universal 3D template
2. Import the provided "BasicGraph.cs" script
3. Create a new Basic Graph (Assets > Create > Graph Toolkit > Basic Graph)
4. Right-Click in an empty space and select "Add Node"
5. Expand the Nodes foldout
6. Click to select the "BasicNode" Node
7. Close the Nodes foldout
8. Observe the Graph window

Actual results: The "Add Node" menu closed itself

Expected results: The "Add Node" menu does not close

Reproducible with versions: 6000.6.0a1, 6000.6.0a5

Not reproducible with versions: 6000.3.16f1, 6000.4.8f1, 6000.5.0b9

Can’t test with versions: 6000.0.0f1, 6000.0.75f1 (due to no Graph Toolkit package)

Tested on (OS): MacOS Silicon Tahoe 26.3